Hey there, I would like to say that this team is a really good OU team that can deal with most threats. Abusing priority moves is an excellent way to pressure the oponent and stop cold any opposing sweep. Unfortunately, this team does not likes burns as the common users of Will-o-Wisp like Rotom-W, Sableye or Jellicent can cause trouble when they switch safely and start spreading burns. To make it worse, your team can´t really switch into a Scald from a bulky Water-type as it will be draining most of its HP. Yes it is true Starmie can absorb it since it has Natural Care, however without Recovery, that equals in suicide.
I see that Mienshao is a pokemon you really like, but if you are willing to change him, I would like to suggest CM Virizion
in his place. Virizion has a higher Speed, won´t mind a Scald burn since he will be using his Sp.Atk, and has Giga Drain recovery making it less of an issue. Virizion by itself can dismantle a lot of Rain-stall teams you might had issues with. Also as a minor suggestion, you might want to run Recover
> Ice Beam, since Starmie is running a Life Orb she will appreciate a recovery move that regains the lost HP from switching into hazards, LO recoil and Sand damage. Hope this rate helps and good luck :). Below is the set.